1. Technical Field
The present invention is directed to a total axis, self adjusting pass-through port. Specifically, the present invention is directed to a pass-through port for use with library storage modules that facilitates various angles between the library storage modules, varying distances between the library storage modules, and varying heights of the library storage modules.
2. Description of Related Art
The use of library storage modules is generally known in the art. Library storage modules allow for the storage and retrieval of thousands of magnetic tape cartridges for use with computing systems. A typical library storage module is described, for example, in U.S. Pat. No. 4,864,511 issued to Moy et al., which is hereby incorporated by reference in its entirety.
It is also known to use pass-through ports to facilitate the passing of magnetic tape cartridges from one library storage module to another. FIG. 1 is a diagram illustrating the prior art pass-through port. As shown in FIG. 1, the pass-through port is comprised of multiple storage cells 132 adapted to ride upon a carriage 384 for transference between the library storage modules. The array of storage cells 132 are spring-loaded upon a pivot 386 attached to the carriage 384, and includes a pair of cam followers 388 adapted to follow a cam surface 390 from one library storage module to the other. The carriage 384 is further coupled to a lead screw 392 by a nut (not shown), which pulls the carriage 384 along the lead screw 392. In order to guide the carriage 384 along the lead screw 392, the carriage 384 is further coupled to a pair of guide rods 396.
When a drive motor 398 rotates the lead screw 392, the carriage 384 is pulled along the lead screw 392 by the nut 394, but the pivoting array of cells 132 following the cam surface 390 enable the cells 132 to be positioned advantageously for incorporation with either library storage module. That is, the array of cells 132 is initially positioned within one library storage module in a manner similar to each of the other storage cells 132 mounted upon the outer housing of the library storage module for access by a robotic arm. Thereafter, upon rotation of the lead screw 392 by the motor 398, the array of cells 132 are rotated, as shown by the dashed arrows in FIG. 1, to a position within the interconnected library storage module for access by its respective robotic arm. The carriage 384 does not enter the arm swing space so that motions of the robotic arm may continue during rotation.
FIGS. 2 and 3 show another prior art pass-through port in which, instead of guide rods 396, the carriage 384a is guided by a simple groove 395 and pin 397 arrangement which maintains its stability. Like the pass-through port 382 shown in FIG. 1, the pass through port 382a includes a pair of cam surfaces 390a and 390b each of which are referenced to their respective library storage modules. A lead screw 392a and nut 394a arrangement provides the motive force for translating the carriage 384a between the library storage modules. A torsion spring 384 is used to pivot the cells 132 just as in the pass-through port 382 of FIG. 1.
These prior art pass-through ports are limited, however, to a specific angle between library storage modules, a specific distance between library storage modules, and library storage modules that are of the same height. As a consequence, the prior art pass-through ports are very difficult to align due to variations in all directions from one library storage module to another. Thus, there is a need for new technology to allow a library storage module to pass tape cartridges from itself to other dissimilar library storage modules or library modules placed in different positions.
The total axis, self adjusting pass-through port according to this invention includes a tape carrier attached to a carriage for movement between two library storage modules (LSMs). The carriage is further coupled to a drive belt and guide rail assembly. The drive belt moves the carriage from one LSM terminal port, associated with a sending LSM, to another, associated with a receiving LSM, when driven by the drive motor. The guide rail assembly guides the carriage along the path between LSM terminal ports. One or both of the LSM terminal ports may be hinged to the guide rail assembly to facilitate varying angles between the LSMs.
The LSM terminal ports are two separate devices that may be mounted on respective LSMs and may be mounted in various positions relative to one another. Thus, the use of the two separate LSM terminal ports helps to facilitate the placement of LSMs in various positions relative to one another and also helps to facilitate the use of LSMs having different radii.
The tape carrier includes a cam follower which follows cam surfaces in the LSM terminal ports as the tape carrier is moved from one LSM terminal port to the other LSM terminal port, and vice versa. The cam follower engaging the cam surfaces provides a mechanism by which the tape carrier is rotated about a pivot such that the tape carrier may be rotated into a position relative to the LSMs that allows an associated robotic arm to retrieve tape cartridges present in the tape carrier.
The guide rail assembly may be comprised of telescopic guide rails having a master guide rail and a slave guide rail which is configured such that it may slide in and out of the master guide rail to thereby provide a telescopic motion of the guide rails. The use of telescopic guide rails in the guide rail assembly allows for varying distances between the LSM terminal ports, and hence varying distances between the LSMs. The varying distances may be a-result of varying angles between the LSMs, varying heights between the LSMs, placement of the LSMs and the like.
As a further feature, the guide rail assembly may include a ball joint for attachment of the guide rail assembly to one or more of the LSM terminal ports. The ball joint provides for three degrees of rotation about an attachment point. Thus, by using the ball joint, the LSM terminal ports may be positioned in varying positions relative to one another. The combination of the ball joint, telescoping guide rails, and the hinged LSM terminal port provides for a tape cartridge pass-through port that is capable of facilitating varying heights, angles, and distances between LSMs.
In addition, the LSM terminal ports may include orientation devices which help to orient the tape carrier so that the tape carrier is in a proper position when engaged with the LSM terminal port. When the orientation devices contact an orientation device engagement device on the tape carrier, the engagement between the two devices causes the tape carrier to orient to a position from which a robotic arm associated with the receiving LSM may retrieve tape cartridges.